Although siege warfare had enjoyed primacy in
the later Roman empire, field forces were not neglected. Horsemen with lances
were trained to dismount rapidly, so that they could fight on foot as
'pikemen', and to vault into the saddle when the time came to fight on
horseback.

The infantry carried less body armour than the
legionaries of earlier days and could deploy more rapidly. Major battles of the
later fourth and fifth centuries illustrate the flexibility of late Roman
battle tactics - for example, Mursa (in 351, fought against Magnentius, who had
usurped the imperial title from the emperor Constans), where lancers dismounted
to fight on foot, or Châlons (451, against the Huns), where imperial infantry
fought in concert with allied Visigothic and Alan horsemen.

Ammianus Marcellinus, a professional soldier
and the leading Roman historian of his day, paid tribute to this flexibility in
his description of the emperor Constantius (d.361): 'He was especially able in
riding, in hurling the javelin and in the use of the bow. In addition, he was
very knowledgeable with regard to all the tactics and armament of
foot-soldiers.'

Throughout the early middle ages, troop
training programmes provide considerable insight into prevailing tactics. In
both East and West, revised versions of Vegetius's Concerning Military Matters,
based upon the earliest surviving revision which was done at Constantinople in
AD 450, abounded.

Although he focused on the training of
infantry (he believed that the mounted arm needed little reform), Vegetius did
devote special attention to the need for tactical flexibility among mounted
troops.

This flexibility was pursued throughout the
middle ages and ultimately it became institutionalized in the 'dragoon', a term
which originally, in the sixteenth century, applied to a mounted soldier
trained to fight on foot.

The following passage was copied and edited by
Rabanus Maurus, a cleric and scholar at the court of the Carolingian king
Lothair Il, who provided an epitome of Vegetius's work which included only
those things which were of importance 'in modern times'. Rabanus selected,
among other chapters, a key element in the training regime for cavalry
recruits:

Wooden horses are placed during the winter
under a roof and in summer in a field. The recruits at first try to mount
unarmed, then they mount carrying shields and swords, and finally with very
large pole weapons.

And this practice was so thorough that they
were forced to learn how to jump on and off their horses not only from the
right but from the left and from the rear and in addition they learned to jump
on and off their horses even with an unsheathed sword.

Mounted troops also trained to fight on
horseback and no less importantly trained their horses for combat. These
training exercises of the early middle ages anticipate the spectacle of the
tournament. Nithard, a grandson of Charlemagne, described a particularly
impressive (but hardly isolated) practice session carried out near Verdun in
842:

For purposes of training, games were often
arranged in the following manner. Fighting men would be deployed in a place
where they could be observed. The entire group...divided into two units of
equal size. They charged forward from both sides and came towards each other at
full speed.

Then [before contact was made] one side turned
its back and under the protection of their shields pretended to be trying to
escape. Then those who had been engaged in the feigned retreat counter-attacked
and the pursuers simulated flight.

Then both kings [Louis the German and Charles
the Bald] and all of the young men, raising a great yell, charged forward
brandishing their spear shafts. Now one group feigned retreat and then the
other. It was a spectacle worthy of being seen as much because of its nobility
as because of its discipline.